docs: def incremental_value(self, slip_moment, mmax, mag_value, bbar, dbar):
          """
          Returns the incremental rate with Mmax = Mag_value
          """
          delta_m = mmax - mag_value
          a_3 = self._get_a3(bbar, dbar, slip_moment, mmax)
          return a_3 * bbar * (np.exp(bbar * delta_m) - 1.0) * (delta_m > 0.0)